Loop aerial



June 1 1926.

M. MATHHESEN LOOP AERIAL Filed Apil 15 IFT l @MUWHHHHHMHHMHML@ Patented `lune l, 1926.

UNiTEosrArns PAT-ENT OFFICE.

MABIUS MATHIESEN, OF ICHICAGQ'ILLINOIS, .ASSIGNOR '10 MATHIESN-SNDBERG i COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

, 1.001 anular..l

Application filed April 13, 1925. Serial No. 22,746.

My invention relates to improvements in aerials for radio systems and has special reference to what are known as loop aerials.

My object is to provide a multiple loop aerial which shall be collapsible into a minimum space for packing and transportation, which shall be of relatively small dimensions when expanded for use and which .shall have fas great eihciency as the larger loops. The usual aerial of this form comprises a collapsible frame on which a plurality of turns of wire are wound, usually in a single uniform helix. In order to make such an aerial 'efficient it is usually more than 2 feet in diameter and contains about 10 turns, in other words, has about 10() feet of wire wound on it.

In my improved form of aerial I use substantially the same lineal lfeet of wire, but I veryy greatly reduce the over all dimensions, thus making the device much neater in lappearance `when distended for use. f

The above result isaccomplished by means of the novel manner in which I wind the wire on the frame. I arrange the aerial wire in the form of a double helix, that is, vone helix within the other, and I arrange the turns in such a manner that the spacing between adjacent turns is as great as in the old form where all the wire iswound in a sing-le helix.

In carrying out my invention I provide a frame, ypreferably collapsible, but of less over all dimensions than the old form, and I provide the cross bars at the ends of the radial arms with two sets of notches, one set deeper than the other, and the shallow and deep notches alternating. Then I wind the aerial wire in the deeper notches to form the inner helix, then I carry the wire back to the beginning and wind it in the shallow notches to form the outer helix.

My improvement consists in the simplified manner in which I produce a condensed loopV aerial, viz, one helix within another and all of the turns effective for the purpose designed. By this means I provide a collapsible loop aerial which can be collapsed to occupy a minimum of space, much less than that of the usual collapsible loop aerial, and much simpler in construction and less expensive to manufacture.

My invention will be more readily under- Stood by reference to the accompanying drawings forming part `of this specication and in which Figure -1, is a side elevation of a loop aerial made in accordance with my invention;

Figure 2, is a fragmentary, vertical section on the -line 2-2 of Figure 1, and

Figure 3,'.is a view similar to Figure 2 but illustrating another manner of arranging the intermediatek connect-or.

In `saidfdrawings, 10 represents generally a collapsible framework on which the aerial wire 11 is wound. Y

In the form of fra-me shown the mast consists of a lower tubular part 12 adapted to be swivelly mounted on a suitable base 13, and an upper part 14 adapted to be telecoped down into the tube 12 when the frame is collapsed. In addition to the mast the frame has two arms 15, 15, hinged at their inner ends vto the upper end of the tubular part 12 and adapted to swing down alongside the part 12, as shown in dotted lines, when the frame is collapsed.

At the lower end of the tubular part I provide a cross-piece 16 rigidly secured thereto yand serving as a cross-arm lto receive the aerial wire 11. I also provide similar cross-arms 17 at the outer ends of the arms 15, anda similar cross-arm 18 at the upper end of the `upper part 14 of the mast.

Each yof the cross-arms is provided with two series of notches 19 and 20. These notches are adapted to receive the wire `11 when it is wound on the frame. The notches l1%) are shallower than the notches 20 and as the wire is wound on the frame, the turns are drawn down against the bottoms of the notches. The deeper notches alternate with the shallow notches so that one set of turns of the wire is within the other set of turns.

In winding the wire 11 on the frame I preferably begin at one end of the lower cross bar 16 securing the end 21 to the bar 16 by a binding screw 22. I provide the end 21 long enough for properly connecting the loop in circuit. Ithen start winding the wire 11, in the nearest deep notch, as shown at 23, winding it around the frame in the similar deep notch in each of the cross-arms and then into the second deep notch, as shown at 24, and in like manner clear across the cross-arms in all of theV deep notches until it reaches the last deep notch, as shown at 25, thus completing substantially one-half of the loop in the forni of an inner continuous helix.

To complete the loop I carry the wire back to the beginning end of the cross-arm 16, as shown at 2G, carrying it over the top ot the crossbar 16 and down on the opposite side so that I can begin winding the wire in the shallow notches 19 at the same end and in the same direction that the outer helix is wound, that is, I begin the outer helix at the point 27. I then complete the loop by winding the wire successively in the several shallow notches beginning at 27 and winding continuously across the cross-bars to the last shallow notch. I then secure the end 28 of the wire to the cross-arm 16 by a binding screw 29. I now have an inner helixBO and an outer helix 31, the turns of both of which are similar and cumulative in their action. Furthermore, the staggering ot' the turns by reason ot the alternating notches of diil'erent depths results in an adequate spacing of adjacent turns and permits the use of shorter cross-arms and a smaller frame than where the whole wire 11 is wound in a single helix, as is common practice.

To thoroughly insulate the cross-connect ing part 26 of the wire troni the tube 12, l pass it through a suitable insulating tube 32 and, as some radio sets require a divided loop, I provide a third connecting end joined to the part 26 o3 the wire 11, that is, connected to the loop between the two parts thereof.

In Figure 3 I have shown another manner of arranging the cross-connecting part ot' the wire 11. In this form instead of carrying this cross-connecting part 34 from the last deep notch up and over the crossbar 16, I carry it straight across just outside ot' the inner turns and through the first deep notch 2&1, just outside of the iirst turn, to the opposite side ot the crossbar and then back through the iirst shallow notch 19, from which point I proceed as before. The eross-connecting portion 311 thus finally occupies a position between the outer helix and the inner helix, as clearly shown in `Figure 3. It is to be noted that all of the turns of both the outer and the inner helix are maintained parallel with each other.

The method o'tl winding described results in a framework with shorter arms and hence collapsible into a smaller compass while yet presenting the required length of aerial tor satisfactory results.

ris many modifications of my invention will readily suggest themselves to one skilled in the art, I do not limit or conline my invention to the specific details of construction and arrangement of parts herein shown and described.

I claim:

1. In a multiple loop aerial, a i'rame consisting oi" a two-piece mast, one piece arranged to telescope within the other, a pair of horizontal arms adapted to be extended in conjunction with the mast to form a cross, crossbars at the ends ot the mast and the horizontal arms, each crossbar formed to hold the wire in the form ot an inner helix and an outer helix, a cross-wire connecting two opposite ends of the two sets of turns, the other ends being available for connecting the device in circuit and a third connecting wire connected to the cross-wire.

In a multiple loop aerial, a trame having cross-arms, a wire wound on the crossarnis and arranged in the form of an inner helix and an outer helix, a cross-wire connecting two opposite ends of the two sets et turns, the other ends being available lor connecting the device in circuit and a third connecting wire leading to the cross-wire.

In a multiple loop aerial, a traine, a wire wound on the frame in two sets ot' turns forming an inner and outer helix of substantially equal length ot' wire, the wires terminating at the bottoni of the frame, a cross-wire connecting two opposite ends ot the two sets of turns, a connecting wire joined to the cross-wire, and the remaining ends of the sets of turns being available for connecting the device in circuit.

In testimony whereof, I have hereunto set my hand, this 1st day ot' April, 1925.

MARIUS MATHIESEN. 

